Study On Electrical Property Of BNT-based Ceramic Material

Doped Y2O3and La2O3to Na0.5Bi0.5TiO3ferroelectric ceramic were synthesized by conventional solid state reaction. The results of XRD diffraction show that,in the doping range discussion, all the ceramics possess a pure perovskite structure and no second phases are observed, and the diffraction peak are shift right. It can be explained by the doping ionic radius and oxygen vacancy for this phenomenon. In the BNT-x%Y2O3system, there is no obvious influence on dielectric constant but a decrease on dielectric loss in the doping range. The sample dielectric loss reaching to the minimum hardly depended on temperature at x=0.2. In the BNT-x%La2O3system, the dielectric constant and loss have close relationship to the measurement frequency as La3+doping, and all samples get the highest test date at10kHz. The sample dielectric loss decreases with the increase of test frequency and is not sensitive to temperature changes.BNT-xCZO ceramics were prepared by non-uniform doping method with preparing CaZrO3(CZO) and pure BNT by solid phase method. The result of XRD indicate that all the samples have formed a stable perovskite structure. A secondary phase was detected at x≥0.25. This is mainly because the solubility of CZO about15%mol exists in BNT ceramics. The temperature-dependent dielectric constants and dielectric loss graph show that the doping of CZO can decrease the dielectric constant and loss of samples. As the increase of CZO, the dielectric constant diminish and be not sensitive to temperature. By test samples piezoelectric properties, the result means CZO did not improve the piezoelectric properties of BNT ceramics. The hysteresis loop indicate there is strong semi conductive at x=0.25.